496 SUMMARY OF CURRENT RESEARCHES RELATING TO 



oesophagus, opening on the internal surface of the base of the mandibles. 

 The secretion has a strong odour, and is probably of protective value. 



Oogenesis in Lepidoptera.* — K. Griinberg finds that in Bombyx 

 mori and Pieris brassiere the differentiation of the cellular elements of 

 the ovary occurs during the larval period. The oogonia, which are 

 derived from the primitive germ-cells, produce only oocytes and nutritive 

 cells. The epithelium of the stalk of the ovarioles is formed from 

 small nuclei which are seen in early stages behind the primitive ovarian 

 tubules. After the differentiation of germ-cells has set in, the epithe- 

 lium of the stalk of the ovarioles forms follicle-cells. Thus germ-cells 

 and follicle-cells have a separate origin, and the latter are genetically 

 equivalent to the cells of the efferent canal. 



f}, Myriopoda. 



New Clasping-Organ in a Centipede.f — K. I. Pocock has de- 

 scribed in certain species of the neotropical genus Parotostigmus a pair 

 of movable — apparently sexual — processes arising one on each side from 

 the inner surface of the femur of the legs of the posterior pair. In an 

 Ecuador species there are very distinct claspers. These take the form 

 of a stout slightly incurved process jutting backwards from the inferior 

 angle of the coxa of each of the legs of the twentieth pair, and reaching 

 to about the middle of the sternal plate of the twenty-first leg-bearing 

 somite. 



Four distinct kinds of secondary sexual characters are now known in 

 the males of Parotostigmus : the femoral process of the anal legs, the 

 coxal claspers above referred to, the modification of the last tergal plate 

 in P. caudatus, and the modification of the tibial segment of the anal 

 leg in P. tibialis Brol. It is significant that the claspers may be corre- 

 lated with the femoral processes, but the two other male features exist 

 independently of the femoral processes, and functionally replace them. 

 The only other genus of Scolopendridse in which similar femoral pro- 

 cesses have been described is the remarkable African form Alipes 

 {Eucorybas), and there are probably affinities between the two genera, 

 — a view quite in keeping with the faunistic similarities that obtain in 

 other respects between tropical Africa and South America. 



5. Arachnida. 



Irish Fresh-water Mites. J — J- N. Halbert notes that most of these 

 agree in their characteristics with common and widely distributed species. 

 Yet interesting forms occur which are little known, while a few are new 

 to science. He proceeds to describe certain of these uncommon species : 

 Hydrachna incisa sp. n., H. dissimiiis sp. n., H. biscutata Thor., Arrhen- 

 urus freemani sp. n., A. ornatus George, A. dilatatus sp. n., A. affirm 

 Koenike, and A. sculptus sp. n. 



Species of Ixodidse.S — L. G. Neumann, speaking ex cathedra as a 

 specialist on mites, points some useful morals to species-mongers. He 



* Zeitschr. f. wiss. Zool., lxxiv. (1903) pp. 327-95 (3 pis.). 



t Ann. Nat. Hist., xi. (1903) pp. 621-4 (1 fig.). 



\ Zool. Anzeig., xxvi. (1903) pp. 2(35-72 (14 figs.). 



§ Mem. Acad. Sci. Toulouse, ser. x. vol. ii. (1902) pp. 329-38. 



